Limiting global warming to 1,5°C is the common goal of the worldwide economies. On this basis Europe has launched its Green Deal, and the European Commission has proposed its Fitfor55 Program reducing the tank to wheel CO2 emissions from transport by 55% in 2030, and by 100% in 2035. Meeting such Tank to Wheel (TtW) emissions requires carbon free energy carriers for all type of mobile applications. In line with the focus of this year SIA Powertrain and Energy conference on passenger cars and all types of commercial vehicles, this paper will describe the use of ammonia as a carbon free fuel. All aspects from production of ammonia, through its transport and its distribution to the service station are considered. Then the storage of ammonia onboard the vehicle and its use in the vehicles' powertrain are laid out and described. The ammonia ecosystem is compared with other carbon free powertrain solutions in terms of overall energy efficiency, CO2 emissions and Total Cost of Ownership (TCO). An example of Light Commercial Vehicle (LCV) application is detailed in this article.